Makefile: add PERLLIB_EXTRA variable that adds to default perl path

diff --git a/RelNotes b/RelNotes
index da6e81321a332fc7c7229c04e438f4161f27755d..61c3b54134d985cef6071014604d5b0499712df5 120000 (symlink)
--- a/RelNotes
+++ b/RelNotes
@@ -1 +1 @@
-Documentation/RelNotes-1.6.1.2.txt
\ No newline at end of file
+Documentation/RelNotes/1.8.5.txt
\ No newline at end of file